Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

HI;

I have a Murray with a 17hp OHV Tecumseh on it.  It is about 10 years old, but only has 50 to 75 hours on it.  The carb was replaced less than 10 hours ago.  There is clean fuel in it, and there is a clean fuel filter in line.  Spark plug is about 10 hours old, and is on my list to replace.  Air Filter is clean.

The mower will run, and at times, it will run very well for a minute or two, cutting heavy grass with what seems like little effort.  Then it will just die, most of the time no sputter, the engine is just off.  I disengage the deck, and it always restarts.
Then I try again, sometimes it will run again for a few minutes with load, other times, it wont even drive up a mild incline with the blade off, without dieing.  I stop and it always restarts.  This same things happens when the engine is cool or if I have been going though this whole starting stopping thing for 3 hours, so it seems unrelated to engine temperature.

I read many post with suggestions on what to try if a engine just loses power, but the thing that is weird is that this will run with Full power for a minute or two, then it dies.  Then the next time I start it, it will kind of chug along, and eventually die, then the next time, it will run with full power again.  I have losened the gas cap.  It idles fine with no load applied.

I tried to watch the governer arm while I am driving it when it dies, and it doesn't look like it even attempts to adjust the engines power before it dies.  Many times it is dieing with very very low load, and even had died when the blades are off.

The service shops that I would take it to are 2 weeks+ backed up, and we have 3.5 acres that is growing.  My dad has worked on old jeep motors quite a bit from the 1940's and 1950's, but has not worked much with smaller engines like this one, and we are not quite sure what could be causing a problem like this.

Does anyone have any suggestions as to where we might want to start?

Thanks So Much
Jamie

  One thing to check since you had the carb removed/ changed is the govenor linkage.  This sounds like a  fuel issue.  one thing to check under load is the throttle of the carb going to full open when driving and the deck is engaged under load..

If the govenor linkage or spring is not adjusted right it may only be running up too 3/4 throttle under load.  Hense only 75 or 50%of you horsepower is available. 

Think of it as having a small wooden block stuck under the gas pedel of your car....  the car WILL get up to full rpm under no load in you drive way parked but will not get up the on ramp at the freeway..

Your engine on your mower is not controlled by the throttle position on the dash, it is controlled by the govenor assy and linkage.  You put you input to the govener (maintain Speed),   and the govenor opens the throttle shaft on the carb as the load increases (to maintain engine speed).

.... or your deck/seat safetie  kill switch is going out..

Good Luck,

Friiy

get yourself an inline spark tester.  remove plug boot hook the tester up.   when tractor start dying check tester, it has a clear window in it to see spark,  does the spark sputter or just stop????  now you say with the deck removed it runs fine??   check fuel filter or replace it.   does this engine have a fuel pump on it or is it gravity feed??   check your safety switch on the deck  make sure its in good condition not cracked and shorting out.